In order to meet wireless data traffic demands that have increased after system commercialization, efforts to develop an improved 5G communication system or a pre-5G communication system have been made. For this reason, the 5G communication system or the pre-5G communication system is called a beyond 4G network communication system or a post LTE system.
In order to achieve a high data transmission rate, implementation of the 5G communication system in a millimeter wave (mmWave) band (such as, 60 GHz band) is considered. In order to reduce, in an ultra-high frequency band, the path loss of an electric wave and increase the transmission distance of an electric wave, technologies such as a beamforming, a massive MIMO, a Full Dimensional MIMO (FD-MIMO), an array antenna, an analog beamforming, and a large scale antenna has been discussed for the 5G communication system.
Further, technologies such as an evolved small cell, an advanced small cell, a cloud Radio Access Network (cloud RAN), an ultra-dense network, Device to Device communication (D2D), a wireless backhaul, a moving network, cooperative communication, Coordinated Multi-Points (CoMP), and interference cancellation to improve the system network have been developed for the 5G communication system.
In addition, the 5G system has developed Advanced Coding Modulation (ACM) schemes such as Hybrid FSK and QAM Modulation (FQAM) and Sliding Window Superposition Coding (SWSC), and advanced access technologies such as Filter Bank Multi Carrier (FBMC), Non Orthogonal Multiple Access (NOMA), and Sparse Code Multiple Access (SCMA).
In the above-mentioned 5G communication system, when a Wireless Access Point is changed according to the movement of a user, a Radio Access Technology (RAT) used in the access point may be frequently changed. A bandwidth provided to a User Equipment (UE) may be greatly changed according to such a change of the RAT. For example, let us assume a communication system including a first base station, which uses a frequency band (e.g. 2 GHz) according to a 4G communication system, and a second base station, which uses an ultra-high frequency band (e.g. 28 GHz).
If a UE changes a wireless access point from the first base station to the second base station or adds the second base station so as to concurrently use two wireless access points, then a bandwidth provided to the UE may increase up to several tens to several hundreds of times. On the contrary, if a UE changes a wireless access point from the second base station to the first base station, or if the UE releases a connection to the second base station while concurrently using two wireless access points including the first base station and the second base station and then uses a wireless access point of the first base station, then a bandwidth provided to the UE may decrease by up to several tenths or several hundredths.
However, since a TCP protocol does not provide a way to provide data in response to such a rapid change of the bandwidth, it takes a predetermined time until a transmission device based on the TCP protocol controls a data transmission rate according to the bandwidth.
Further, the efficiency of a frequency resource is reduced until the transmission device based on the TCP protocol controls the data transmission rate.